Ole Gunnar Solskjaer said Edinson Cavani will be ready to face his old club Paris Saint-Germain in the Champions League on Wednesday despite the distraction of a Football Association investigation into a social media post by the Uruguayan.
Cavani's joy at coming off the bench to turn a 2-0 deficit into a 3-2 Premier League win at Southampton on Sunday with two goals and an assist was tempered as after the match he thanked a friend for his congratulations on Instagram using the Spanish term "negrito" (small black person).
Despite the affectionate context, Cavani could still fall foul of the FA's minimum three-match ban for offensive comments on social media.
"He's deeply sorry for the mistake he's made. There was no malicious intent at all, it was just an affectionate greeting to a friend of us and we explained to him," said Solskjaer at Tuesday's pre-match press conference.
"We'll support him, it's one of those unfortunate situations, he's just come into the country and in Uruguay it is used with a different affection to what we have.
"We'll support him but of course we support the FA. It's important the FA ask him to explain and it's out there for everyone to see because we want to be in the fight against discrimination with everyone."
Cavani is PSG's all-time top goalscorer after scoring 200 times in seven seasons in the French capital.
But he was let go when his contract expired in June, not even hanging around for PSG's run to a first ever Champions League final in August.
After taking time to find his feet in Manchester, Cavani's impact at the weekend has put him in line to start up front in a huge game against his former club.
PSG trail United by three points at the top of Group H and face an embarrassing early exit if they lose at Old Trafford.
"He's ready to play, it's special for him to play against PSG, his own club where he's the top scorer," added Solskjaer.
"That'll affect him mentally, but from knowing him, that will give him energy and he'll be ready. He's so professional, experienced he'll work on his mindset today to be ready for the game.
"The same goes to for the FA (investigation), he's learned a lesson, it might affect him but he'll just have to put it to one side when the game is on. The best players can put their problems or other thoughts away for a while then perform when he has to."
Solskjaer confirmed that David de Gea will be fit to start in goal after coming off at half-time against Southampton.
Anthony Martial and Paul Pogba are also in contention to return, but Pogba may have to settle for a place on the bench.
Without the French World Cup winner in the starting line-up, Donny Van de Beek has finally managed to get a run in Solskjaer's side as United have won four consecutive games to climb back into contention for the Premier League title.
Van de Beek spent most of his first few months in Manchester on the bench, but the £40 million ($53 million) signing from Ajax always believed he just had to be patient.
"I know I can give the team something extra and I can help the team a lot, so I was just patient," said the Dutch international.